The invention relates to a method for obtaining non-magnetic ores from a suspension-like mass flow containing non-magnetic ore particles.
The use of flotation cells for obtaining ores from ore-containing bulk material is well known. A mass flow in the form of an ore-containing pulp, i.e. substantially a suspension of water, ground rock (gangue) and ground ore is fed to a flotation cell or a flotation reactor.
In the context of “magnetic flotation” methods, the mass flow containing the pulp is loaded (in a “load process”) with magnetic particles, which may be, for example, magnetic particles in the form of magnetite, to form ore particle-magnetic particle agglomerates. In order to form the ore particle-magnetic particle agglomerates, prior hydrophobization both of the ore particles and of the magnetic particles is usually required. The formation of the ore particle-magnetic particle agglomerates thus produced substantially by hydrophobic interactions or by attractive forces is achieved by mixing the starting materials in a mixing apparatus, taking account of particular mixing parameters such as shear forces, time, temperature, etc.
The mass flow containing the ore particle-magnetic particle agglomerates is then fed as a “separator feed flow” to a (first) separating device in the form of a magnetic separator. The magnetic separator serves to separate the ore particle-magnetic particle agglomerates from the mass flow or pulp, that is, the magnetic ore particle-magnetic particle agglomerates are extracted from the pulp and are transferred to a “separator concentrate flow” which substantially contains the ore particle-magnetic particle agglomerates, small quantities of gangue material and water. The remaining constituents or residues (known as “tailings”) are fed to a separator residual flow.
Subsequently, the ore particle-magnetic particle agglomerates are split into the constituents thereof, specifically ore particles and magnetic particles, so that said materials are present together but unbound or separately in the form of a mixture (in an “unload process”). Typically, the separation of the ore particle-magnetic particle agglomerates is carried out by a further or second separating device with chemical processes by the use of suitable chemicals such as solvents or the like.
The separation of the magnetic particles which are present substantially in isolation, from the ore particles and the other constituents is also carried out subsequently in the context of the “unload” process using a further or third separating device, again typically in the form of, or comprising, a magnetic separator in which the magnetic particles are magnetically separated. Thereafter, separation takes place into a first mass flow containing magnetic particles and a second mass flow containing ore particles, which are present separately from one another and substantially or ideally contain only the respective pure material, that is, either pure magnetic particles or pure ore particles.
A method of this type is disclosed for example by EP 2 090 367 A1, which relates to a method for the continuous recovery of non-magnetic ores from a pulp containing non-magnetic ore particles. In said process, magnetic or magnetizable magnetic particles are fed to a pulp continuously flowing through a reactor, said magnetic particles forming ore-magnetic particle agglomerates with the non-magnetic ore particles. The ore-magnetic particle agglomerates are moved into an accumulator region of the reactor and then guided out of the accumulator region of the reactor by a magnetic field.
With the known method, it is often problematic for the separation of the relevant ore particle-magnetic particle agglomerates from the separator feed flow to be realized with sufficient efficiency. Separation of all the ore particle-magnetic particle agglomerates from the separator feed flow is usually not possible, that is, a certain residue of unremoved ore particle-magnetic particle agglomerates remains in the separator residual flow. This primarily arises firstly for statistical reasons, according to which a particular content of ore particle-magnetic particle agglomerates cannot be removed from the separator feed flow, and secondly due to the efficiency of the magnetic separator (first separating device) used for separating the ore particle-magnetic particle agglomerates from the separator feed flow.
Therefore, a certain amount of loss occurs in relation to the overall process, with regard to both the ore particles and the magnetic particles, because both the non-agglomerated ore particles and the magnetic particles as well as the ore particle-magnetic particle agglomerates not separated from the separator feed flow are not available for further use, or only with significant effort. No monitoring of the process for forming the ore particle-magnetic particle agglomerates, nor any monitoring of the process for separating out the ore particle-magnetic particle agglomerates from the separator feed flow take place.